1. Field of the Invention
The present invention relates to an insect repellent composition that achieves effective insect repellency with a relatively low concentration of a natural ingredient, oil of citronella. The present invention also relates to an insect repellent composition that provides ultraviolet (UV) sunscreen protection from both UVA and UVB radiation. In addition, the present invention relates to an insect repellent composition that provides ultraviolet protection and that is also water resistant/waterproof.
Insects are not only a nuisance to consumers who enjoy outdoor activities, but insects are also known to be carriers of disease. Mosquitoes, in particular, may act as vectors for diseases such as malaria and encephalitis.
In addition, the same outdoor daytime activities that expose consumers to disease-carrying insects, such as mosquitoes, also expose consumers to the damaging effects of UV exposure from the sun. Scientific literature has provided an abundance of documentation regarding the harm caused by extended, unprotected exposure to UV radiation. Consumers are also aware of the potential damage that results from extended, unprotected exposure to UV radiation and thus, prefer skin products that offer UV protection.
Consumers, who expose themselves to both insects and UV radiation during outdoor activity, often perspire or are exposed to water in other ways. As a result, it is important to provide an insect repellent composition that has water resistant/waterproof properties along with insect repellency and sunscreen activity.
N,N-diethyl-m-toluamide (DEET) is a presently available synthetic insect repellent that has demonstrated superior insect repellency in comparison to previous prior art natural insect repellents. However, there is concern that repeated DEET exposure may have harmful consequences. For example, possible DEET side effects are irritability, confusion, insomnia, and even seizures. For these reasons, caution is generally recommended with regard to the use of DEET as an insect repellent. This is especially true when DEET is applied to children, who are more susceptible to the potentially injurious effects of exposure to DEET.
Presently, there are products available that use floral or herbal extracts to provide insect repellency. There are even insect repellent products that contain oil of citronella. However, these prior art insect repellents have not been able to provide adequate insect repellency to meet consumer needs while primarily using a concentration of oil of citronella of about 0.08 wt % to about 0.12 wt %. (All percentages disclosed herein are weight percentages of the total composition unless otherwise specified.)
2. Description of the Prior Art
The use of oil of citronella in insect repellent products is known. However, high levels of oil of citronella have previously been required to provide the levels of insect repellency desired by consumers. Hence, oil of citronella is usually added to insect repellent products primarily as a fragrance, rather than primarily as an agent for insect repellent activity.
However, there have been previous attempts to produce an effective insect repellent product using only a relatively small concentration of oil of citronella. For example, U.S. Pat. No. 5,227,406 to Beldock et al. discloses insect repellents that contain at least 0.01% terpineol (preferably 0.06%), at least 0.01% citronella (oil of citronella, preferably 0.05%), at least 0.01% rhodinol extra (preferably 0.08%), and at least 0.01% geraniol (preferably 0.06%).
U.S. Pat. No. 5,346,922, also to Beldock et al., discloses insect repellents that contain at least 0.01% terpineol, at least 0.01% citronella (oil of citronella), and either at least 0.01% rhodinol extra or at least 0.01% geraniol. Preferably, the components are present at between 0.05% to 0.08%. Both the Beldock et al. ""406 patent and the Beldock et al. ""922 patent disclose that a sunscreen may be incorporated into the insect repellent compositions disclosed in each respective patent.
U.S. Pat. No. 5,621,013, also to Beldock et al., discloses insect repellents that contain approximately 0.05% citronella (oil of citronella), approximately 0.06% geraniol, approximately 0.08% to 0.5% crystalline 3,8 P-menthanediol, and approximately 0.06 terpineol and/or approximately 0.08% rhodinol (extra). The compound 3,8 P-menthanediol is a crystalline compound that is a naturally occurring component of a Chinese herb.
U.S. Pat. No. 5,648,398 discloses that a fragrance may be added to the insect repellent compositions disclosed in U.S. Pat. Nos. 5,227,406 and 5,346,922.
The insect repellent compositions disclosed by the Beldock et al. patent contain oil of citronella. Oil of citronella, a natural product, is composed of many chemical compounds, among which are terpineol, rhodinol and geraniol. The Beldock et al. repellent then augments oil of citronella with various combinations of additional amounts of terpineol, rhodinol, or geraniol. The result is that the finished repellent compositions disclosed by the Beldock et al. patents have a final concentration of terpineol, rhodinol or geraniol that is greater than that which is naturally present in oil of citronella.
It is an object of the present invention to provide an insect repellent composition that does not contain DEET and that is effective while utilizing only about 0.08 wt % to about 0.12 wt % oil of citronella.
It is also an object of the present invention to provide an insect repellent composition that provides average insect repellent protection time of greater than two hours.
It is another object of the present invention to provide an insect repellent composition that provides UVA/UVB protection.
It is still another object of the present invention to provide an insect repellent composition that both provides UVA/UVB protection and that is water resistant/waterproof.
It is further an object of the present invention to provide an insect repellent composition that may be used in a vehicle that contains alcohol as a primary ingredient and that contains little or no added water.
It is another object of the present invention to provide an insect repellent composition in a pleasant smelling, moisturizing, elegant and non-greasy alcohol-containing formulation.
It is yet a further object of the present invention to provide a liquid insect repellent composition that may be topically applied directly on human skin.
It is still yet a further object of the present invention to provide an insect repellent composition that may be topically applied either as a spray product or in a towlette.
To accomplish the foregoing, the present invention is, in brief summary, a topical composition that comprises about 0.08 wt % to about 0.12 wt % oil of citronella, about 20 wt % to about 40 wt % emollient and up to 15 wt % C12 to C15 alkyl benzoate (also known in the art as xe2x80x9cC12 to C15 alcohols benzoatexe2x80x9d) in an alcohol-containing vehicle that is suitable for topical application. The composition may also include an UVA/UVB sunscreen. In addition to the UVA/UVB sunscreen, the composition may also be formulated to have water resistant/waterproof characteristics.
The present invention is a composition that provides insect repellency. The composition includes oil of citronella, a emollient and certain C12 to C15 alkyl benzoate (also known as xe2x80x9cC12 to C15 alcohols benzoatexe2x80x9d) in an alcohol-containing vehicle suitable for topical application.
The present invention is a composition that provides insect repellency that comprises about 0.08 wt % to 0.12 wt % oil of citronella, about 20 wt % to about 40 wt % emollient, and about up to 15 wt % C12 to C15 alkyl benzoate, with the remainder being an alcohol-containing vehicle suitable for topical application. All percentages set forth herein are percentages by weight of the total composition unless otherwise specified. Preferably, the insect repellent composition comprises about 0.09 wt % to about 0.11 wt % oil of citronella, about 25 wt % to 35 wt % emollient, and about 2 wt % to about 8 wt % C12 to C15 alkyl benzoate, with the remainder being an alcohol-containing vehicle suitable for topical application. More preferably, the insect repellent composition comprises between about 0.09 wt % to about 0.11 wt % oil of citronella, about 29 wt % to 31 wt % emollient, and about 4 wt % to about 6 wt % C12 to C15 alkyl benzoate, with the remainder being an alcohol-containing vehicle suitable for topical application. Most preferably, the insect repellent composition includes about 0.1 wt % oil of citronella, about 30 wt % emollient, and about 5 wt % C12 to C15 alkyl benzoate, with the remainder being an alcohol-containing vehicle suitable for topical application.
Although the resultant insect repellent composition has about 0.1 wt % oil of citronella, the resultant composition exhibits an unexpectedly high degree of insect repellent activity. The applicants do not wish to be bound by any theory, but it is believed that the combination of the oil of citronella, the emollient and the C12 to C15 alkyl benzoate produce a synergism that creates an effective insect repellent composition.
The emollient should have the following properties: good spreadability, chemical stability and miscibility with alcohol. Any emollient that exhibits the above-identified characteristics may be used to practice this invention. Examples of emollients contemplated for use in the insect repellent composition are fatty alcohols, fats and oils, hydrocarbons, ethers and esters. Specific examples of these types of emollients are listed below in Table 1. Preferably, the emollient is an ester. The preferred emollient ester may be isopropyl myristate, isopropyl palmitate, or a combination thereof. The most preferred emollient ester is isopropyl myristate.
Fatty Alcohols
octyldodecanol
cholesterol
cetyl alcohol
Fats and Oils
caprylic/capric triglyceride
hydrogenated palm oil
sesame oil
lanolin oil
Hydrocarbons
mineral oil
petrolatum
isoeicosane
Ethers
dicapryl ether
dimethyl isosorbide
Esters
isopropyl myristate
isopropyl palmitate
benzyl laurate
butyl octyl salicylate
butyl oleate
canola oil
C12-C15 alkyl octanoates
C10-C30 cholesterol/lanosterol esters
cetyl isononanoate
dicapryl adipate
dilauryl citrate
glyceryl monooleate
glycol dilaurate
isosorbide monolaurate
jojoba oil
Esters (Continued)
myristyl lactate
octyl palpitate
PEG-7 glyceryl cocoate
proylene glycol myristyl ether acetate
retinyl palmitate
tallow glycerides
tocopheryl acetate
Any C12 to C15 alkyl benzoate known in the art may be used in the present invention. The most preferred C12 to C15 alkyl benzoate is available from Finetex under the registered trademark Finsolve TN.
The preferred vehicle for the insect repellent composition is alcohol-containing and contains little or no added water. More preferably, the vehicle contains no added water. The preferred vehicle contains about 20 wt % to about 50 wt % of any suitable cosmetic grade alcohol. Preferably, the cosmetic grade alcohol is a denatured alcohol. More preferably, the alcohol will be xe2x80x9cspecially denaturedxe2x80x9d (SD). The most preferred alcohol is SD alcohol 40 B.
The vehicle may also contain up to 50 wt % of a volatile silicone. The volatile silicone acts to improve the feel of the insect repellent composition against the skin. Preferably, the volatile silicone will comprise about 5 wt % to about 40 wt % of. the total weight of the composition. The preferred volatile silicone is cyclomethicone.
Preferably, the vehicle contains an antioxidant. The preferred antioxidant is butylated hydroxytoluene. The antioxidant is present from about 0.01 wt % to about 0.1 wt % of the total weight of the composition.
Preferably, the vehicle also contains a fragrance that will provide a pleasant smell to the present invention, but will not adversely affect the effectiveness of the insect repellent composition. More preferably, the fragrance will be present at about 0.1 wt % to about 1.0 wt % of the total weight of the composition. Most preferably, the insect repellent composition has about 0.5 wt % of a fragrance.